Currently, electrical devices such as tachograph devices, satellite navigation systems, cameras, and mobile communicating devices (namely, mobile phones), have multiple functions and bring convenience for people in daily life, enabling people to obtain the newest information wherever they are, through these devices.
Generally, the electrical device is operated under the supply of the power source assembled therein; once the power source lacks power, the electrical device is connected with the supply mains via a connecting cable.
Taking the vehicle charger as an example, two ends of the vehicle charger are respectively the vehicle charging connector and the USB connector, so that the vehicle charging connector is inserted into the inserting hole of the cigarette lighter, and the USB connector is connected to the electrical device for charging the electrical device. However, when drinks or water are spilled onto the USB connector, terminals, circuit boards or other electrical components in the USB connector will short-circuit since the vehicle charging connector is electrified (namely, the vehicle charging connector is connected with the cigarette lighter).